Method and apparatus for precooling freight cars



Jan. 13, 1948. I PREBLE 2,434,432

METHOD AND APPARATUS FOR PRECOOLING FREIGHT CARS Filed March 13, 1944 2 Sheets-Sheet 1 Jan, 13, 1948. I A. Y. PREBLE METHOD AND APPARATUS FOR PRECOOLING FREIGHT CARS Filed March 13, 1944 2 Sheets-Sheet 2 Patented Jan. 13, 1948 METHUD AND APPARATUS FOR PRE- COULIN G FREIGHT CARS Andrew Y. lPreble, El Centro, Calif.

Application March 13, 1944, Serial No. 526,301

7 Claims.

This invention relates to the precooling of cargoes, and is particularly useful for precooling freight cars used for transporting vegetable or fruit products. The freight cars employed for shipping fruit, usually have side doors located pposite to each other at the middle of the car, and they have ice bunkers at their ends. It has been the practice heretofore to precool such cars by closing one of the side doors, and by placing a false door in the opposite doorway, the said false door being provided with an inlet duct and an outlet duct through Which cooled air is circulated through the car from an air cooling plant lo cated alongside of the car, A precooling plant for this purpose must have a considerable cooling capacity for withdrawin the heat from the atmospheric air, and the construction and operation of such a plant involves a very considerable expense.

One of the objects of this invention is to provide a simple method for effecting the precooling of a cargo space of a, car, which will eliminate the use of a cooling plant such as referred to above, and the incidental expense involved in the construction and operation of such a plant; at the same time, providing a method for precooling, which will be emcient in operation, but which will entail the use of only very simple circulating apparatus, and which utilizes the ice in the ice bunkers of the car to effect the cooling of the air within the cargo space.

The idea of circulating the air within the cargo space of a freight car through its ice bunkers to precool the same, is not broadly new, but the apparatus for accomplishing this usually requires a special construction for the interior of the car, or has other disadvantages involving the use of a circulating plant for withdrawing the air at the car door, and forcing the same back through the cargo space and through the bunkers.

One of the objects of the present invention is to provide a simple method for circulating the air from the interior of the cargo space through the ice bunker, or ice bunkers of the car, which can be practiced through the agency of very simple apparatus, and avoiding the necessity for establishing circulation through the car door.

Another object of the invention is to provide apparatus of simple construction that can be applied to an ordinary air-cooled freight car without necessitating any reconstruction of the car, but which will adapt the same for practicing my precooling method.

The freight cars that are employed for shipping vegetable and fruit products, usually have an ice bunker at each end, and the crates carrying the vegetable products or fruit, are charged into the car so as to leave a narrow entry-or space popularly called the squeeze, and which is located opposite the doorways and between the two end loads in the car. One of the difiiculties encountered in attempting to circulate air through such a cargo space, is that unless properly guarded against channeling in the air movement will occur. This term channeling is applied to describe a movement of air in which an air stream is developed flowing directly from the point of admission of the air to its point of exit. And, of course, when channeling occurs, the circulating effect is incomplete and ineficient as there will be little precooling eifect in any pockets or spaces through which the air is not forced to circulate.

One of the objects of this invention is to provide a method and apparatus that will operate in such a way as to prevent the development of any'serious channeling effect.

Another object of the invention is to provide simple apparatus that is particularly adapted for use with my method, for effecting precooling of the cargo space in a car, through the agency of circulation of the air through the ice compartments.

The invention consists in the novel method, and in the apparatus to be described hereinafter, the features of which all contribute to produce an eflicient method and apparatus for precooling freight cars.

A preferred embodiment of the invention is described in the following specification, while the broad scope of the invention is pointed out in the appended claims.

In the drawing:

Fig. l is a vertical section through the ice bunker of a freight car, taken about on the line l-l of Fig. 2, and looking toward the partition or bunker wall between the ice and the cargo space of the car.

Fig. 2 is a horizontal section upon an enlarged scale, taken about on the line 2-2 of Fig. 1, and passing through the bunker wall that separates the ice bunker from the cargo space. This view illustrates the apparatus shown in Fig. 3, as applied to the screen of the bunker wall that covers the usual upper opening that opens communication between the interior of the bunker and the cargo space in the car. ,In this view certain parts are broken away and shown partially in section and diagrammatically. The outline of the car wall and bunker space is indicated, While the position of the hatch at one side of the car is indicated in dotted outline. In this view, the body of the car is broken away.

Fig, 3 is a perspective of a portion of the apparatus that I employ, and which is illustrated in Fig. 1, when the invention is applied to a car that is already built. The portion of the apparatus illustrated in this figure, is applied within the bunker to the inner side of the inner screen covering the upper opening of the bunker that opens communication to the cargo space. In this view the inlet end of the circulating duct is illustrated, and the upper portion of the duct is broken away.

Fig. 4 is a section taken about on the line 4-4 of Fig. 1, and passing through a baffled duct that I prefer to use as an accessory to the apparatus for the purpose of breaking up and distributing the air stream that is forced down through the ice in the bunker.

Fig. 5 is a diagrammatic longitudinal section through a car, and illustrating diagrammatically the manner in which my method operates to efiect circulation of the air from the ends to the middle portion of the car, and the means that I may employ at the central portion to assist in preventing channeling of the circulated air.

Before proceeding to a more detailed description of the invention, it should be explained that this invention must be regarded in two lights, or from two angles. As illustrated in the drawin and specification, the invention is described as applied to a car that is already built, and which has an upper opening through the partition wall that separates the ice bunker from the cargo space of the car. When applying my invention to a car of the usual construction, and having such an opening, I blank off a substantial portion of the area of this opening, and I withdraw the air from the interior of the car through the remaining area of this opening, and then force the same down through the interior of the ice bunker. In this way the heat is extracted from the air. These iced cars also have a bottom opening through the bunker wall just below the grating floor on which the cargo is placed, and in accordance with my method, I force the air down through the ice in such volume and at such velocity as to build up a pressure in the ice bunker that is above atmospheric pressure. This is done so that when the air current projects itself through the bottom opening in the bunker wall, it will flow with considerable velocity away from the immediate vicinitv of the ice bunker. This development of a sufiicient pressure in the ice bunker is important, because it prevents a defect in circulation, which is popularly known as channeling, which term is usually employed to describe a conditionin which air that is forced into a confined space, tends to move in a direct line toward the outlet from which air is withdrawn from the confined space.

Practically all iced freight cars have an ice bunker in each end, and in accordance with my method I provide for circulating air from the interior of the cargo space through each ice bunker, and this air, after passing down through the bunkers, is caused to flow with considerable velocity toward the middle portion of the car where the squeeze is located, that is to say, where a space is located between the end loads, and in which braces are placed to keep the loads from shifting longitudinally in the cargo space.

Also when applying the invention to the usual iced freight car, I utilize the customary two hatches that are provided in the car roof over the ice bunkers, and which are employed for enabling the bunkers to be effectively filled with broken ice properly distributed throughout the horizontal area of the bunker. Accordingly, in accordance with my invention as applied to such a car, I provide apparatus that I set in place over these hatches after removing the hatch covers, and this apparatus includes a blower or fan that withdraws the air from the cargo space through the unblanked remaining portion of the upper opening, and forces the same down through the ice bunker. It should be understood, however, that my invention is not limited necessarily to the method and apparatus which I employ when applying my invention to a car that is already built. My invention can be applied in a car constructed in any way, which will permit air to be withdrawn from the interior of the cargo space, forced down through the ice compartment, and conducted partially, if not wholly, along the car floor under the grating, to the squeeze" space at the middle of the car. My invention includes steps and apparatus that I employ in connection with the squeeze space, to insure efiective circulation of the air through the upper levels of the cargo in the vicinity of the middle portion of the car,

I shall now describe the invention as applied to a freight car I having two ice bunkers 2 and 3, one located in each end of the car (see Fig. 5). As the ice bunkers are identical in construction, and my method and apparatus is applied to each ice bunker, it will be necessary only to describe one of the circulating units that I employ, and the manner in which it cooperates in the practice of the method with the unit at the other end of the car to develop a plenum chamber effect" at the middle of the car, which enables my invention to operate most effectively.

Referring to the ice bunker 2 that is illustrated in Figs. 1 and 2, it should be noted that the bunker wall 4 that separates this bunker from the cargo space 5 within the car, has the usual upper opening 6 which is usually covered with wire screens 1 and 8. This opening cooperates with a bottom opening 9 (see Fig. 5) that is formed in the partition wall 4 near the bottom, developing circulation of air through the ice bunkers. The iioor of the car is provided with the usual floor grating Ill which rests on longitudinal stringers II that divide the transverse space below the bars of the grating I0, into a plurality of guide channels or rudimentary guide ducts l2 which extend longitudinally of the car under the grating. These longitudinal ducts or guide channels have been employed before in circulating systems, and I utilize these ducts in the present system, to conduct air cooled by the broken ice l3 in the bunkers; they operate to conduct this cold air toward the middle portion of the car, and thi circulation is promoted by means that will presently be described. An iced car such as described, is usually provided with two hatch openings l4 and I5 (see Figs. 1 and 2), which are formed in the roof over each bunker.

In accordance with my invention, I provide a panel l6 preferably formed of sheet metal or similar material which is illustrated in detail in Fig. 3, and which is also shown in Fig. 2, Thi panel operates as a cover that substantially covers a considerable portion of the opening 6 through the upper portion of the bunker wall 4, and I attach this plate IE to the inner side of the inner screen I that covers this opening. This panel [6 is preferably made as an extension of the forward flange ll of an inlet [8 that operates as the mouth of an uptake elbow 19 that connects with circulating means to withdraw air from the cargo space 6 and circulate the same down through the ice in the adjacent ice bunker 2. Any suitable means may be provided for attaching this inlet H? and the plate IS in position against the screen. In the present instance, I have illustrated afastening device 20' for this purpose, which includes a long threaded stem 2|, the inner endof which isprovided with a pivoted crossbar 22; also the inner end of this stem is formed with a point 23. The other end of the stem 2? is provided with a head 24 and a wing nut 25. This fastening is constructed to enable its point to bepushed through the mesh of the screens 1 and 8 from the inside of the bunker, and after the point 23 has penetrated far enough to enable the cross bar 22 to be rotated out of alignment with the axi of the stem it, the stem is then shaken andpulled back so as to seat the inner side of the cross bar 22 against the face of the screen 8. Then the wing nut 251s screwed up on the threads to clamp these parts in position. One of these fastenings should be used at about the middle of the plate It, and would be applied through an opening 26 provided for enabling the stem 2| of the fastening to be passed through the plate. And the inlet 18 is provided with a cross bar 21 at about its middle, which may be a horizontal bar as illustrated, or a vertical bar, if desired; and this bar 21' has an opening 28 throughit corresponding in function to the hole. '26 that i formed at about the middle of the plate [6. Additional clamping means may be provided if desired, around the flange l1, and around the edges of the plate Hi, to hold them more securely in position. Such additional. fastenings, however, are not illustrated as they do not concern the invention.

On the coaming 29 of the. adjacent hatch opening it, I eat the flange 30 of the uptake elbow Ill. The wall of this elbow continues downwardlyinto the hatch opening past the flange 30, and is connected by means of an accordion connection 3! of canvas, duck, or similar material, to a lower uptake elbow 32 that extends back from the inner end of the inlet l8 which preferably has converging side walls that converge toward each other as they recede from the flanged end or mouth of the inlet (see Fig. 2).

The upper uptake elbow i9 is formed as an integral part of the horizontal tubular extension 33 from a housing for the blower or fan that is employed for driving the inducted air down through the ice bunker, and I prefer to mount the blower housing of blower 34 directly over the hatch I5; and I provide a base flange 35 that seats on the hatch coaming 36 on this side of the car. The flanges 30 and 35 are preferably inclined slightly to bring them into the plane of the upper edges of the coamings on which they seat. If desired, a rubber gasket can be applied between the flanges 3!! audit, and their corresponding hatch coamings, to make a substantially air-tight connection if desired. However, a I drivethe blower 3'4 with ample power, a slight leak in the circulating system would be oi slight consequence. The blower 34'may be of anysuitable type adapted to induct the air from the tubular duct 33 and force the same down through the hatch l5, and from there down through the broken ice'in the ice bunker.

In order'to drive the blower, its shaft 3'! is provided with a belt pulley 38 which is driven by a belt 39 that runs down from an electric motor 40 mounted onthe upper side of the blower housmgl Referring again to Fig. 5, the crates M are charged into the car through its side doors, and are piled up: on each other toward each end of the car so that two end loads 52 and 43 are formed, the adjacent ends of which are disposed apart at the squeeze 44 that has been. referred to above, and at which braces (not illustrated). are employed to hold the end loads against movement. In the operation of my method, I drive each blower at sufficient speed to supply the circulated air to the squeeze 54. in sufiicient volume and velocity to develop this middle space as a plenum chamber. In order to accomplish this, the blowers must be driven at suflicient speed to compensate for the loss of air that will occur as the air currents pass along the longitudinal channels E2; in other words, to compensate for a considerable quantity of air that passes up through the spaces between the grating bars, as indicated by the arrows in Fig. 5. These currents of air that pass up through the grating, are of course desired, and assist in attaining an effectual. precooling of the entire cargo space. Howover, due to the relatively low pressure that is developed by the blowers at their inlets [3, there is a tendency for the air that comes up through these grating openings, to make a beeline for the nearest suction inlet H8. The establishment of the plenum chamber at the middle of the car is. most advantageous, because it insures that the suction efiect. at the inlets I8, cannot channel away all of the air that comes up through the grating before the circulating stream arrives at the plenum chamber 44. If that happened, of course there would be a tendency to produce a dead pocket in the vicinity of the point 35, as indicated in Fig. 5;

In order to increase the plenum chamber effeet at the squeeze 44, I prefer to provide a rudimentary cover or bafile 45 that restricts more or less upward flow of the air that arrives at the lower portion of the plenum chamber. This prevents air from passing up in the squeeze and taking the line of least resistance up toward the roof of the car. This baflle 46 is preferably in the form of an inverted channel, the flanges of which project downwardly. This channel, of course, extends all the way across the car, and has the effect of a rudimentary hood under which air' currents rising in the squeeze (it, will be obstructed and caught. In practice, it would be desirable to have this baiile or hood 6 mounted so that its level could be adjusted with respect to the level of the upper crates 4| of the cargo.

In addition to the bathe 46, I may also provide a bottom bafile which, in the present instance, is in the form of a plate 41 that lies on the upper face. of the floor grating at the bottom of the squeeze. The use of this plate is optional, and its use and its area would depend somewhat on how the air circulation developed at the bottom of the squeeze. When the plate is in position, there is a tendency of the two air currents coming from the opposite ends of the car, to counteract each other and develop a slight elevation in pressure under the plate, and this of course would tend to back up in the longitudinal channels I2 toward the ends of the car, thereby increasing the pressure in the channels [2, which is desirable, particularly in the vicinity of the middle portions of the cargo.

The: broken ice I3 charged into the bunkers, is preferably of the usual form of irregular broken lumps of ice, as this facilitates passage of the circulating air readily through the gaps or interstices between the irregular chunks of ice. However, if desired, I may employ a baflle duct 48 (see Figs. 1 and 4) for baffling the air current as it comes down from the blower, and for causing it to distribute itself more uniformly throughout the broken ice. For this purpose, the baffle duct 48 is employed, and this duct preferably is disposed in an inclined position as shown, so that its lower end is located at about the middle of the transverse bottom opening 9. I prefer to construct this duct so that it presents a plurality of transverse baffle plates 49, each of which is provided with a plurality of openings 50. These plates are held in place by corner angle bars 5| that extend longitudinally of the bafile duct, and give it its form. The angle bars 5| are preferably enclosed in a continuous wall 52 of wire mesh that is wrapped around the outside of the angle bars 5|. The edges of the baffle plates 49 may be provided with flanges 53 that can be riveted or welded, or otherwise secured to the inner angles of the angle iron bars 5|.

The car bottom 54 is provided with the usual drain openings 55, which may be provided with trap ducts 56 that have outwardly inclined delivery necks 51 that let the water drip down at the side of the trap.

In order to facilitate the mounting of this apparatus on a freight car that is constructed as described, it may be desirable to have the inlet |8 detachably mounted on the end of the lower uptake elbow 32. If that is desired, it may be readily accomplished by providing the side walls |8a of each inlet with a vertically extending channel-form flange 58, and the adjacent end of the uptake elbow 32 is provided with a laterally disposed flange 59 that slides into this channel 58. In using the apparatus in some cars, this detachable suction inlet might facilitate passing the inlet and lower elbow 32 down through the hatch separated from each other, and then united by a man standing inside the bunker, thereafter. who would connect these parts together after attaching the inlet I8 and the blanking plate Hi to the inner side of the screen wall 1.

The general mode of operation of my invention will now be briefly described. When the blower 34 is driven by its electric motor 40, it should be driven at a sufficiently high R, P. M. to insure a rapid circulation of the air through the cargo space and through the bunkers in considerable volume, and this speed should be sufficient to insure that the air that passes down through the ice bunkers and through their bottom outlets 9, cannot be channeled by the suction effect of the inlets l8 so as to develop merely a local circulation at each end of the car. A contrary effect is attained by reason of the energetic circulation of the air, which insures that regardless of the loss of air that passes up through the gratings Hi as indicated by the arrows in Fig. 5, a considerable quantity of air arrives at the middle of the car and under the squeeze 44 where the continual arrival of this air develops a plenum chamber effect. The effect of this plenum chamber can be regulated by the character and level of the baffle 45, which acts as a long hocd extending all th way across the car, and under which the air collects to develop this plenum chamber effect. In this plenum chamber a slight increase of air pressure above atmospheric pressure is attained, and from both sides of this plenum chamber the air finds its way through the 8 upper levels of the cargo in the vicinity of the "squeeze. This effectively prevents formation of any dead air pockets in the middle portion of the car, and operates to enable the car to be precooled by this method in a relatively short period of time.

Of course, if the air in the cargo space of the car is at a relatively high temperature, an appreciable loss in weight of the broken ice l3 in the ice bunkers will result, and it will therefore be necessary in most cases to replenish this consumed ice before the car departs for its destination.

Many other embodiments of the invention may be resorted to without departing from the spirit of the invention.

What I claim is:

1. In apparatus for precooling a freight car having a floor grating and ice bunkers at its ends, with hatches through the car roof, and having bottom and upper openings through the bunker wall into the cargo space of the car; the combination of means for covering a portion of the upper opening through the bunker wall, a duct in the upper portion of the bunker having an inlet substantially covering the remainder of said upper opening, a duct located above the car roof and seating over the hatch opening that lies adjacent to said inlet, and means connected with the lastnamed duct for withdrawing air from the duct and from the cargo space through the said inlet, and for forcing the air down through the other hatch opening, through the ice in the ice bunker and back into the cargo space through the said bottom opening.

2. Apparatus for precooling a freight car according to claim 1, in which the circulating means for the air includes a blower housing and a blower within the same, seated over the other hatch opening and delivering the circulating air directly through the hatch opening into th bunker and through the ice within the same.

3. Apparatus for precooling a freight car according to claim 1, including a bailling duct extending down through the interior of the bunker for conducting the circulating air through the ice, and operating to break up and distribute the current of circulating air passing down through the bunker.

4. In apparatus for precooling a freight car having an ice bunker at each end, a bottom grating in the freight car between the bunkers and a bottom opening from each bunker at a lower level than the bottom grating communicating with the cargo space in the car; the combination of means for closing off communication between the upper end of each bunker and the interior of the cargo space, a duct having an inlet for withdrawing air from the cargo space, and for conducting the air up through the car roof, means mounted on the car roof for withdrawing air from the cargo space through said duct and inlet, and for forcing the same down through the roof of the car through the adjacent bunker, so that the air circulated down through the ice will pass out through the bottom opening of each bunker and flow toward the middle portion of the cargo space.

5. Apparatus for precooling a freight car according to claim 1, including means located in the interior of the bunker for breaking up and distributing the current of circulating air passing down through the bunker.

6. A method of precooling a freight car having a fioor grating, an ice bunker with hatches through th car roof, the freight car having bottom and upper openings through the bunker wall into the cargo space and having the floor grating at the bottom of the cargo space between the ice bunkers which consists in loading the cargo space so that a chamber is left in the cargo space at a distance from the bunkers, blanking ofi a portion of said upper opening that is located toward one side of the car, Withdrawing air from the cargo space through the remaining open area in said upper opening, circulating the air down through the ice compartment and thence from the bottom of the bunker wall in a longitudinal direction of the car under its floor grating, cooling and receiving a portion of the air so circulated in the cargo space chamber, and restricting the flow of the air upwardly in said chamber to attain a plenum efiect in the said cargo space chamber.

7. A method of precooling a freight car having a floor grating, an ice bunker with hatches through the car roof, the freight car having bottom and upper openings through the bunker wall into the cargo space and having the floor grating at the bottom of the cargo space between the ice bunkers; which consists in loading the cargo space so that a chamber is left in the cargo space 10 at a distance from the bunkers, blanking off a portion of said upper opening that is located toward one side of the car, withdrawing air from the cargo space through the remaining open area in said upper opening and outwardly through one of the hatches, blowing such withdrawn air down through the other hatch through the ice bunker and thence from the bottom of the bunker wall in a longitudinal direction of the car under its floor grating toward said chamber.

ANDREW Y. PREBLE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

